6.  The applicant was born in 1952 and lives in Montana. At the material time she was employed as a neurologist at Montana Regional Hospital and was on occasion called upon to act as a court‑appointed expert.
7.  On 9 January 2001 the Montana police were tipped off that the applicant, while acting as an expert appointed by the Montana Regional Court to draw up a report in connection with a civil claim brought by a Ms A.G. against her employer, had asked Ms A.G. to pay her money in exchange for her drawing up a report corroborating her claim. The next day, 10 January 2001, the police requested the Montana Regional Court (Окръжен съд Монтана) to issue a warrant allowing them to install covert listening devices in the applicant's office in the hospital and in her private practice, and secretly to mark banknotes which Ms A.G. would hand to the applicant. On 10 January 2001 the court's president, exercising his powers under section 15 of the 1997 Special Surveillance Means Act (see paragraph 22 below), issued a warrant, specifying that the covert surveillance was not to exceed thirty days. The warrant did not mention the applicant's name or the registration number of the request; however, both the request and the warrant bore the number under which the request had been registered at the court. On 11 January 2001 the Montana police informed the chief secretary of the Ministry of Internal Affairs about the warrant by telephone and at 6.30 p.m. the same day received instructions from him to start the covert operation. The next day, 12 January 2001, the Minister of Internal Affairs also gave his written approval.
8.  The technical department of the Ministry of Internal Affairs then installed the listening devices. At about 3 p.m. on 15 January 2001 Ms A.G. met with the applicant in front of and then inside her private practice. Their conversation was surreptitiously recorded. Ms A.G. handed the applicant two banknotes which had previously been marked by the police with a special material which glowed under ultraviolet light. Immediately after that the police searched the premises and found the two banknotes in the applicant's purse and seized them. They were later tested by a police expert.
9.  The same day, 15 January 2001, the Montana District Prosecutor's Office charged the applicant with bribe‑taking.
10.  On 7 February 2001 the three officers of the Ministry's technical department who had carried out the surveillance drew up a transcript of the audio recording which they had made on 15 January 2001. The transcript said that the recording had started at 2.30 p.m., but did not mention when it had ended. They also made a copy of the audio recording, from the original cassette onto a second one. One of the copies of the transcript was sent, along with the first cassette, to the Montana Regional Court. The second copy of the transcript and the other cassette were sent to the Montana police.
11.  On 21 May 2002 the prosecuting authorities submitted an indictment against the applicant to the Montana District Court (Районен съд Монтана). On 17 June 2002 the judge-rapporteur at the Montana District Court set the case down for trial. However, at the first hearing, held on 17 October 2002, the court, noting that the indictment had not been drawn up properly, referred the case back to the prosecuting authorities.
12.  On 27 December 2002 the Montana District Prosecutor's Office re‑submitted the indictment.
13.  On 9 February 2003 the judge-rapporteur at the Montana District Court set the case down for trial. Hearings were held on 27 March and 5 June 2003. On the latter date the court, noting that as a result of an intervening amendment to the 1974 Code of Criminal Procedure cases concerning bribe‑taking became triable by regional courts, discontinued the proceedings and sent the case to the Montana Regional Prosecutor's Office.
14.  However, following a further amendment to the Code of Criminal Procedure providing that pending cases were to be completed under the old jurisdictional rules, on 25 June 2003 the Montana Regional Prosecutor's Office sent the case back to the Montana District Court, and on 21 July 2003 the court decided to resume the trial. It held hearings on 16 October and 10 November 2003. The applicant was able to acquaint herself with the material obtained through the covert listening devices and listen to the audio recording, which was played in the courtroom. At both hearings counsel for the applicant objected to the admission in evidence of, inter alia, the material obtained through the covert listening devices. The court rejected the objections and decided to admit that material in evidence. In her closing speech counsel for the applicant reiterated the objections, pointing out that the surveillance warrant did not contain a reference to the number of the request, and that the transcript of the audio recording did not mention the time when the surveillance had come to an end, which had made it possible to manipulate the transcript and present the words spoken by the applicant out of context.
15.  In a judgment of 10 November 2003 the Montana District Court found the applicant guilty of aggravated bribe‑taking, contrary to Article 305, read in conjunction with Articles 301 § 1 and 302 of the Criminal Code (see paragraph 33 below). It sentenced her to three years' imprisonment, suspended, and barred her from being a court‑appointed expert for three years. It found that instead of examining Ms A.G. in the hospital, she had invited her to her private practice and had asked her to pay her money in exchange for a favourable expert report.
16.  The court based its findings of fact on, among other evidence, the testimony of Ms A.G. and her husband, the search conducted by the police on 15 January 2001, the evidence gathered through the covert listening device in the applicant's private practice, and two expert reports drawn up by a police expert and showing that the applicant had touched the marked banknotes that she received from Ms A.G.
17.  The court went on to analyse in detail the applicant's objections against the admission of various items in evidence. It held, inter alia, that the failure of the judge who had issued the surveillance warrant to mention the number of the request was not a problem, because neither the 1997 Special Surveillance Means Act nor the 1974 Code of Criminal Procedure required that. The failure to refer, in the transcript of the audio recording, to the request for the use of special surveillance means, the surveillance warrant or the Minister's decision authorising their use, or to specify in the transcript the time when the recording had ended, were not in breach of the statutory requirements either, and the procedure followed by the authorities to obtain permission for the covert recording and to carry it out had been proper. The transcript fully complied with the applicable rules, and there was no indication that phrases spoken by the applicant or Ms A.G. had been taken out of context. Both of them had heard the recording during the trial, and had stated that the voices in the recording had been theirs and that the recorded phrases had been spoken by them. The expert reports had been prepared in line with the relevant statutory and regulatory requirements, and there were no grounds to disqualify the expert who had drawn them up. Her conclusions had been based on the presence of a special material produced by the technical services of the Ministry of Internal Affairs on the applicant's hands and on the two banknotes. The composition of that material, which was not being used in any other domain, was secret.
18.  On 24 November 2003 the applicant appealed against her conviction and sentence. She reiterated her objections against the admission of the evidence obtained through the covert listening devices, and argued that the reasons given by the district court for rejecting her objections in that respect were erroneous. She also impugned the expert's refusal to disclose the exact composition of the material used to mark the banknotes, and argued that the expert was not impartial because she worked for the regional directorate of the Ministry of Internal Affairs – the very body which had sought permission to use special surveillance means against the applicant and whose officers had marked the banknotes.
19.  The Montana Regional Court heard the appeal on 26 January 2004, and on 2 February 2004 upheld the applicant's conviction, but reduced her sentence to one and a half years, suspended. In the reasons for its judgment it stated, among other things, that it fully agreed with the detailed and comprehensive reasons given by the district court to reject the applicant's objections against the admission of certain items in evidence. It went on to say that the failure of the judge who had issued the surveillance warrant to mention the number of the request was not sufficient to taint the evidence obtained through the covert listening devices.
20.  On 2 March 2004 the applicant appealed on points of law. She reiterated her arguments in relation to the evidence obtained through the covert listening devices and the expert evidence, and argued that the regional court had failed to give sufficient reasons for its judgment and to address key arguments relating to the wrongful admission of evidence.
21.  The Supreme Court of Cassation (Върховен касационен съд) heard the appeal on 13 October 2004 and dismissed it on 28 December 2004 (реш. № 644 от 28 декември 2004 по н. д. № 229/2004 г., ВКС, ІІ н. о.). It noted that the applicant's arguments were the same as those that she had raised before the lower courts. The fact that the regional court's reasons were not detailed was not a problem, because it had stated that it fully agreed with the reasons given by the district court. It also held that the evidence against the applicant had been properly admitted. There had been no serious breaches of the 1997 Special Surveillance Means Act or the 1974 Code of Criminal Procedure in relation to the use of covert listening devices. The applicant had been fully acquainted with the material obtained through the use of those devices and had recognised her own voice. The failure to mention the number of the request for use of special surveillance means and to include in the transcript the exact time at which the surveillance had ended were mere technical errors which could not affect the validity of the evidence obtained through the use of such means. The court went on to say that the expert's reports were comprehensive and complete, that they had not been the only evidence proving the applicant's guilt, and that there had been no grounds to disqualify the expert.